A bluebird sighting was becoming a rarity 35 years ago when a small group of bird lovers created the Bluebird Recovery Program of Minnesota.

Threatened by competition from other tree cavity-dwelling birds and a loss of habitat, the songbird known as the harbinger of happiness was going through a decidedly somber period.

The Bluebird Recovery group, a committee of the Audubon Chapter of Minneapolis, built and hung birdhouses and in its first year reported 22 fledglings that flew the nest.

Thirty-three years later, in 2012, the group of volunteers set a record with more than 23,000 fledglings sighted across the state.

Today, eastern bluebirds can be seen along trails, in parks, on golf courses, on school and corporate campuses and even in cemeteries, thanks to the recovery group's efforts.

Among them are birds hatched at two state parks in Washington County, Afton and William O'Brien, and the nonprofit Belwin Conservancy in Afton.

The Minnesota Department of Natural Resources (DNR) credits the recovery program and the agency's Nongame Wildlife Program with fostering one of the most successful bluebird recovery projects in the nation.

For the most part, program participants aren't scientists, just grass-roots volunteers smitten with the plump birds with blue backs and rust-colored bellies, said Carrol Johnson, the statewide coordinator for the recovery program.

Johnson, a retired 3M maintenance supervisor living in Northfield, started fawning over the bluebird about a dozen years ago after reading a newspaper article and attending a lecture.

"I never even knew there was a need," said Johnson, who now maintains and monitors about 60 bluebird houses in Northfield and on his farm in Fillmore County. He also fields dozens of calls a week from bluebird volunteers across the nation.

People fall hard for the little songbird, he said.

"It happens to a lot of our people. People come to our presentation inquisitive. Some people get really hooked," Johnson said. "They really enjoy the process of seeing the birds building the nest, laying the eggs and hatching."

Monitoring houses is critical. Unmonitored houses can actually hurt bluebirds by attracting nonnative sparrows and increasing their population, Johnson said.

On the watch in Afton

Volunteers mount, monitor and maintain thousands of bluebird houses across the state. Two examples are Chuck and Hope Lea, longtime volunteers at Belwin, who have been checking bluebird houses along the Bell Oak Savanna trail for 20 years.

Chuck Lea, a retired 3M chemical engineer, keeps careful track of the number of eggs and how many birds were fledged. The figures fluctuate from year to year, mostly owing to predators such as house wrens, which punch holes in the eggs. Lea counted the most eggs, 85, in 1998; his highest fledgling count was in 2009, with 57.

"People are really drawn to the beauty of that bird and they have a lovely, warbling little call," said Lynette Anderson, naturalist and restoration assistant at Belwin. "They bring with them a general good feeling. They speak to people's hearts."

According to Afton State Park naturalist Linda Radimecky, Afton environmentalist Oliver Charley created the region's first bluebird trail on land now belonging to the state park because he loved the "little gems of blue."

Today the park has 120 bluebird houses, some on the trails and others out on the prairie, and all of them maintained by dedicated volunteers. O'Brien State Park has even more houses, she said.

"It's not unusual to see a bluebird flying around out here," Radimecky said. "I hear them singing all the time, especially this time of year."

In Dakota County, a group of "bluebird engineers" maintains bluebird houses on Flint Hills Resources property in Rosemount, including 500 acres of restored habitat along the Mississippi River.

Four Flint Hills employees led by senior process engineer Renee Smith volunteer for bluebird duty. So far, they've counted 53 fledglings and another two dozens eggs ready to hatch. They will report their results to the recovery program this fall.

Smith spends about an hour a week checking the bluebird boxes and doing any necessary maintenance. Gnats, which kill hatchlings, can be a problem, so they spray the boxes with cooking vanilla as a deterrent.

Smith, who has always had an interest in nature and conservation, took over bluebird duties in 2012.

"The are so pretty. It's amazing to see these birds," she said. "It interesting. I like being able to hopefully make a difference."

Labor of love

In Anoka, retired school principal Jeanne Wilkinson and retired schoolteacher Dick Sherva check on 39 bluebird houses at sunrise every Wednesday. Both active in the Friends of the Anoka Nature Preserve, they have counted more than 50 fledglings so far this year.

Six years ago, Wilkinson took over the bluebird "trail" first established by another bird lover who had died; she assumed the duties at the request of his widow. She wears an apron to carry odd items and tools she may need — a stick to dig out an old nest, a plastic sack to bag it.

The Anoka bluebird trail includes birdhouses at two cemeteries, the old state hospital campus, the community garden, the county fairground, local parks and the nature preserve.

"Every week you go out, you never know what you'll find," Wilkinson said.

Wilkinson conscientiously records her findings at each birdhouse each week. She peeks in, looking for new nests, newly laid blue eggs and new hatchlings.

Other native cavity-dwelling birds — black-capped chickadees, wrens and swallows — will sometimes claim a house. Wilkinson waits for their eggs to hatch and those babies to fledge before cleaning out the box for a bluebird. Volunteers will remove the nests and eggs of the invasive English House sparrow.

A lot of the job is housekeeping — keeping the houses in good repair and cleaned out. Bluebirds, known for their meticulous, neat nest building, often won't use a box if it's already stuffed with an old, trash-laced nest from another songbird.

Whether to intervene

Some critics say it's not good to tinker with nature's balance. But Wilkinson and Sherva assert that it's human interference that caused bluebird numbers to drop in the first place.

People introduced the English house sparrow, a bluebird predator, to the eastern United States in the 1800s. People also destroyed bluebird habitat and chopped down dead trees with cavities where they like to nest.

Now human intervention has brought them back. "Making bluebird houses and monitoring them is critical," Wilkinson said.

On this Wednesday, Wilkinson finds several bluebird nests with pale blue eggs that are warm to the touch. In four houses, she finds families of hatchlings — two bluebird clans, black-capped chickadees and tree swallows.

It's not all good news. One house that last week had warm eggs has been opened and emptied. Wilkinson investigates the scene on his knees, theorizing that the birdhouse is too low and a raccoon may have plundered it.

"You become very protective of your babies and eggs, They are such beautiful birds," Wilkinson said.

Staff writer Kevin Duchschere contributed to this report.

Shannon Prather • 612-673-4804